<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <button>后退</button>
    <script>
        console.log(history.length);

        var btn = document.querySelector("button");
        btn.onclick = function () {
            // 后退
            // history.back()
            // 后退一页
            history.go(-1)
        }
    </script>

</body>

</html>